Individual self-contained device for measuring ionising radiation

Abstract

The individual self-contained device for measuring at least one ionising radiation type comprises: - at least one sensor (52) which senses each said ionising radiation type and provides an electrical signal representative of the quantity of each ionising radiation type, - a wireless signal transmitter (53) designed to remotely transmit data representative of each signal provided by a sensor and - a self-contained power source (54) designed to power each sensor and the transmitter; the sensor, the transmitter and the power source being embedded in a casing (50) with a surface area of less than 60 mm2 and the total weight of the casing, the sensor, the transmitter and the power source being less than 10 g.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a self-contained, individual detection device for measuring ionizing radiation. It is applicable to the field of operator safety in environments where ionizing radiation may be present. STATE OF THE ART

[0002] Regulations require that, during interventions involving ionizing radiation, the risk to operators be assessed and quantified. Risk assessment is carried out through workplace studies. Risk quantification is performed using dosimeters.

[0003] Two main types of dosimeters are used: Passive dosimeters do not provide instantaneous measurements and require subsequent laboratory analysis. These devices are considered the most reliable and are generally used for legal dosimetry. These devices cannot differentiate the day or worksite during which the dose was captured, nor do they provide instantaneous information on the dose rate or the integrated dose.

[0004] Passive dosimeters can be used for: whole body dosimetry allows us to estimate the dose taken by the operator, extremity dosimetry allows us to estimate more precisely the dose taken by the operator at the level of the fingers or the lens of the eye, for example.

[0005] Active dosimeters allow for real-time measurement of the dose rate and dosimetry of operators. These devices provide real-time alerts to the operator, indicating whether they risk exceeding the dosimetry threshold for which their operation was planned during the preliminary study phase. Although these devices are not used for legally mandated dosimetry, wearing them is mandatory because they alert the operator to the danger while providing a quantitative indication. For example, document WO 2015 / 119526 A1 discloses a miniature dosimeter for ionizing radiation, such as one housed in a smartphone, equipped with a microprocessor connected to a control and data transmission interface, which is linked to the mobile device's data and power supply buses. PRESENTATION OF THE INVENTION

[0006] The present invention aims to remedy all or part of these drawbacks and, in particular, to provide an active dosimetry solution for the extremities and the lens.

[0007] To this end, the present invention relates to a self-contained individual device for measuring at least one ionizing radiation, as defined by the independent claim

[0008] The device that is the subject of the invention thus allows its wearer and / or a supervisor to know, in real time, the flux of ionizing radiation and / or the dose integrated by the operator wearing the device.

[0009] The device applies not only to professional operators working in an environment where ionizing radiation may be present, but also, for example, to nuclear medicine, for which the device makes it possible to control, in real time, the dose integrated by an organ or area of ​​the body during radiotherapy, while minimizing the strain on the patient.

[0010] The device of the present invention exhibits a very high degree of miniaturization, despite the constraints associated with electronic components. The object of the present invention enables the capture of ionizing radiation, including Gamma / Beta radiation measured for nuclear applications, by shaping the signal representative of the captured radiation.

[0011] The energy from this radiation is on the order of nanoamperes, which is too low to power the device of the present invention. Therefore, it necessarily requires an additional energy source, which increases the number and size of the components of the device of the present invention, while still keeping them contained within a casing with a surface area of ​​less than sixty mm² and a weight of less than ten grams, so that they can be placed on the extremities or the lens of an operator.

[0012] In embodiments, the device of the invention comprises a bias voltage generator, each ionizing radiation sensor implementing this bias voltage, in which the bias voltage is the output voltage of the autonomous power supply or a stabilized voltage close to the voltage of the autonomous power supply.

[0013] This reduces the number of electronic components in the device, thus improving its miniaturization.

[0014] In embodiments, the device of the invention comprises a single signal processing component configured to perform pre-amplification, amplification and shaping functions of the signal supplied by each sensor.

[0015] This reduces the number of electronic components in the device, thus improving its miniaturization.

[0016] In some embodiments, the single signal processing component features: high input impedance, low input bias current (< 1 pA), low noise (< 10 nV / Hz), wide bandwidth (> 10 MHz).

[0017] These characteristics allow the miniaturization of the device that is the subject of the invention, while ensuring a high signal quality.

[0018] In embodiments, the device of the invention comprises a single component for analyzing the signal provided by each sensor after amplification, this component also comprising the wireless signal transmitter.

[0019] This reduces the number of electronic components in the device, thus improving its miniaturization.

[0020] In embodiments, the device of the invention comprises a single multifunctional component for protecting the autonomous power supply against overvoltages, deep discharges and overheating, for managing the load of the autonomous power supply and for managing the supply voltage of the analysis circuit.

[0021] This reduces the number of electronic components in the device, which improves its miniaturization and autonomy.

[0022] In some embodiments, the power supply management of the enclosure by the single multifunction component is configured to: provide, at most, two different voltages, if there is more than one voltage, the voltages are between half above and half below the autonomous power supply source voltage.

[0023] This reduces the number of electronic components in the device, which improves its miniaturization and autonomy.

[0024] The advantage of these implementations is also to limit the voltage differences between the battery voltage and the voltages required by the system. Since the efficiency of voltage converters is not 100%, limiting voltage differences reduces energy losses and therefore allows the use of a smaller battery for the same operating time.

[0025] In embodiments, the device of the invention further comprises a portable terminal including a receiver of the data emitted by the emitter of the envelope and a means of signaling to the wearer of the miniature envelope when said data represents instantaneous radiation or integrated radiation exceeding a predetermined limit value.

[0026] This portable terminal allows the wearer of the protective envelope to obtain an integrated dose measurement as well as the dose rate at the envelope level, for example, at the operator's hands or eyes. The operator is thus alerted in real time if a dose rate or dosimetry threshold is exceeded.

[0027] In some embodiments, the device of the invention further comprises a local relay for data emitted by the envelope transmitter, a relay configured to retransmit, over a long distance, the data emitted by the envelope transmitter.

[0028] The relay allows information to be transmitted over a long distance, with or without wires, and also to determine the area in which the device is located.

[0029] In some embodiments, the device of the invention further comprises a central receiver of data emitted by the transmitter and a system for managing said data.

[0030] Since each device is linked to a single operator, it is possible to precisely monitor each operator's dosimetry in real time while estimating the ambient dose rates of the environment in which they work. Each supervisor is thus alerted in real time to any dose rate or dosimetry threshold exceeded.

[0031] In some embodiments, the device that is the subject of the invention comprises a ring carrying said envelope.

[0032] This ring, which can be worn on the finger by the operator under protective gloves, allows for extremity dosimetry.

[0033] In some embodiments, the device of the invention comprises a small case including said casing, this case being clippable onto glasses or integrable into a headband.

[0034] This device allows dosimetry to be performed at the level of the lens or any specific part of the body.

[0035] In embodiments, the device of the invention includes a memory of an identifier of the envelope, of a workstation or of the bearer of the envelope, the wireless signal transmitter being configured to remotely transmit this identifier with data representative of each signal provided by a sensor.

[0036] This allows the wearer of the ring to be identified without risk of error in the allocation of measured doses. It also enables the dosimetric data to be classified by monitoring software.

[0037] In some embodiments, the internal space of the casing, between each sensor, the emitter and the power source, is cast in a resin.

[0038] Encasing the internal space of the casing in resin is possible because optimizing power consumption has reduced heat output. The advantage of encasing the device in resin is that it reduces the size of the casing and makes the device more resistant to shocks and vibrations.

[0039] In some embodiments, the transmitter is configured to transmit data over a distance less than the communication distance of a wireless local area network.

[0040] In embodiments, the device of the invention includes a means of detecting the wearing of the envelope by an operator and a means of activating the operation of each sensor and the transmitter of the envelope as soon as the wearing of the envelope by an operator is detected.

[0041] In some embodiments, the envelope includes an autonomous memory for storing captured values ​​and / or calculated values.

[0042] This memory allows for subsequent transmission in the event of a communication failure.

[0043] The various specific features of the present invention are intended to be combined to form different individual autonomous devices for measuring at least one ionizing radiation exhibiting all or part of the advantages set forth above. BRIEF DESCRIPTION OF THE FIGURES

[0044] Other advantages, purposes and special features of the invention will become apparent from the following non-limiting description of at least one particular embodiment of the device that is the subject of the invention, with reference to the accompanying drawings, in which: There figure 1 represents, in block diagram form, a signal processing chain 20 for an ionizing radiation detector of a device that is the subject of the invention, The figure 2 represents, in the form of a block diagram, the functions of an electronic circuit of a device that is the subject of the invention. figure 3 represents a pre-amplification part of the electronic circuit illustrated in figure 2 , There figure 4 represents functions of an electronic circuit of a miniature envelope of a device that is the object of the invention and The figure 5 represents a particular embodiment of the device that is the subject of the invention. DESCRIPTION OF IMPLEMENTATION METHODS

[0045] The present description is given by way of non-limiting attribution, each feature of an embodiment being able to be advantageously combined with any other feature of any other embodiment.

[0046] It should be noted from the outset that the figures are not to scale.

[0047] Throughout the description, the term operator is used both for a professional working in an environment that may present ionizing radiation, and for a patient in nuclear medicine, particularly in radiotherapy treatment.

[0048] It is worth recalling here that ionizing radiation is a form of energy released by atoms that propagates through electromagnetic waves (gamma rays or X-rays) or particles (neutrons, beta particles, or alpha particles). The spontaneous disintegration of atoms is called radioactivity, and the excess energy is emitted as ionizing radiation. Unstable elements that disintegrate by emitting ionizing radiation are called radionuclides.

[0049] All radionuclides are uniquely identified by the type of radiation they emit, the energy of that radiation, and their half-life.

[0050] Activity—which measures the amount of radionuclide present—is expressed in a unit called the becquerel (Bq): one becquerel corresponds to one disintegration per second. Half-life is the time it takes for the activity of a radionuclide to decrease by half compared to its initial value. It is also the time required for half of the atoms it contains to disintegrate. Half-lives can vary from a fraction of a second to millions of years (iodine-131, for example, has a half-life of 8 days, while carbon-14 has a half-life of 5,730 years).

[0051] It is worth recalling here that ultraviolet (“UV”) radiation is not ionizing radiation.

[0052] We observe, in figure 1 A signal processing chain 20 for an ionizing radiation detector. This chain 20 includes a bias voltage 21 and an ionizing radiation sensor 22 implementing this bias voltage 21. The signal output from the sensor 22 is pre-amplified by a preamplifier 23 and then amplified by an amplifier 24. Then, the amplified signal is shaped by a shaping module 25, before being analyzed by an analyzer 26.

[0053] The miniaturization of the device is due in particular to its following technical characteristics: The bias voltage 21 is the voltage of a battery 27, for example, of the LiPo type (3.0 to 4.2 V DC), or a stabilized voltage close to the battery voltage 27, preferably the same as the supply voltage of the preamplifier 34 (2.8 V). The sensor 21 has dimensions of approximately twenty mm², all signal processing is performed via a single component 29, and signal analysis 26 is carried out via a component 33 which includes the wireless signal transmitter 31.

[0054] The electronic circuit is represented in figure 2 It includes a battery management system 32 27 that provides a DC voltage 28, the sensor 22, the signal processing component 29, and the wireless remote transmission and signal analysis component 33. The signal processing component 29 performs the pre-amplification 23, amplification 24, and shaping 25 functions illustrated in figure 1 .

[0055] Signal processing component 29 features: high input impedance, low input bias current (< 1 pA), low noise (< 10 nV / Hz), wide bandwidth (> 10 MHz).

[0056] It is worth recalling here that high impedance is defined in electronics as follows: In electronics, high impedance is the state of an output pin that is not controlled by its component. In digital components, this means that the signal is at a logic level that is neither high nor low. Such a signal can be seen as an open circuit (or as a "floating" wire) because connecting it to a low-impedance component will not affect it. The majority of integrated circuit pins are actually tri-state outputs that are internally connected to inputs.

[0057] In analog electronics, high impedance mode is defined as the absence of low-impedance paths at any of the other nodes. High impedance in analog electronics allows for high amplification with low current consumption.

[0058] Power management by the battery management system 27 (32) is optimized as follows: The number of different supply voltages is limited to two, thus reducing the number of components. Power supply efficiency is improved by using operating voltages close to the battery voltage, i.e., between half the battery voltage (e.g., 3.6 V DC). A signal processing component 29 is selected to utilize the battery's variable voltage range of 3 to 4.2 V DC. Supplying the signal processing component 29 with 2.8 V DC allows full battery charge utilization, thereby reducing the battery size for equivalent autonomy. A single multifunction component 32 is used for battery protection 27 (against overvoltage, deep discharge, and overheating), battery charge management 27, and management of the supply voltage to the analysis circuit 26.

[0059] To optimize the layers of the printed circuit board carrying all the electronic components of the device, the assembly is done on a printed circuit board with six layers, which increases the density of conductive tracks.

[0060] We observe, in figure 3 , the assembly 35 of the operational amplifier 34 performing the pre-amplification.

[0061] The selected components are miniature. Preferably, they are soldered from the underside of the component using micro-beads of tin, which allows for minimal space on the electronic board.

[0062] Because the components have low current consumption, they generate little heat. Preferably, the components and the entire printed circuit board are embedded in resin, which has several advantages. Firstly, it minimizes the size of the enclosure and, secondly, it guarantees the physical integrity of the components against shocks or various mechanical stresses.

[0063] The CSP (Central Signal Processor) is an important element of the analog chain. It transforms the small electrical charges from the radiation / matter interaction inside the sensor into voltage.

[0064] A CSP generates an output signal 38 by charging the capacitance 36 via the sensor loads; these loads are amplified using a feedback loop to obtain a usable output signal 38. The resistor 37 allows the capacitance 36 to be discharged and generates output pulses rather than a high or low state.

[0065] A semiconductor 39 forming a radiation sensor, at the input has an inherent capacitance which gives the circuit additional complexity, compensated by the other capacitances of the assembly, which correspond to the input capacitances of the operational amplifier 34.

[0066] Two stability factors must be taken into account: Resistor 37 must be sufficiently large to avoid introducing noise into the CSP. Values ​​between 10 and 100 MΩ have been experimentally validated; capacitance 36 must be small enough to ensure the fastest possible charge collection from the sensor. Values ​​between 0.5 and 2.0 pF have been experimentally validated.

[0067] We observe, in figure 4 , an envelope 50, with a surface area of ​​less than sixty mm² and a weight of less than ten grams, which comprises, on a printed circuit 51: an ionizing radiation sensor 52, providing an electrical signal representative of the amount of ionizing radiation, a wireless signal transmitter 53 which remotely transmits data representative of each signal provided by a sensor, a bias voltage generator 55, the sensor 52 implementing this bias voltage.

[0068] A self-contained power supply 54 configured to power each sensor and said transmitter is not directly on the printed circuit board 51, but is connected to it by conductive wires.

[0069] The components shown in figure 4 are contained in a miniature and lightweight envelope that can be worn comfortably, in the form of a ring under a glove or on glasses, by an operator, as illustrated in figure 5 .

[0070] Preferably, the bias voltage is the output voltage of the autonomous power supply source 54 or a stabilized voltage close to the battery voltage 27, preferably the same voltage as the supply voltage of the preamplifier 34 (2.8 v).

[0071] Preferably, transmitter 53 is configured to transmit data over a distance shorter than the communication range of a wireless local area network. This reduces the power consumption of transmitter 53.

[0072] Preferably, a single signal processing component 60 performs pre-amplification 56, amplification 57 and shaping 58 functions of the signal supplied by each sensor.

[0073] Preferably, the single signal processing component has: high input impedance, low input bias current (< 1 pA), low noise (< 10 nV / Hz), wide bandwidth (> 10 MHz).

[0074] Preferably, a single component 61 for analyzing 59 the signal provided by the sensor 52 after amplification, also includes the wireless signal transmitter 53.

[0075] Analysis 59 performs the calculation of the ionizing radiation flux as well as the integrated dose by the operator, the transmitter 53 transmitting the calculated values ​​in real time.

[0076] Preferably, a single multi-function component 62 provides the functions 63 of protecting the autonomous power supply against overvoltages, deep discharges and overheating, 64 of managing the load of the autonomous power supply, 65 of managing the supply voltage of the analysis component 61 and 66 of managing another supply voltage of the components of the envelope 51. This reduces the number of electronic components of the device, which improves its miniaturization and autonomy.

[0077] Preferably, the power management 66 of the enclosure by the single multifunction component 62 is configured to: provide, at most, two different voltages, if there is more than one voltage, the voltages are between half above and half below the autonomous power supply source voltage.

[0078] This reduces the number of electronic components in the device, which improves its miniaturization and autonomy.

[0079] Preferably, the autonomous power supply 54 is a rechargeable or disposable battery, associated with a means of wired or wireless electrical power transfer.

[0080] In the embodiment illustrated in figure 4 , the circuit 51 includes a memory 67 of an identifier of the envelope 50, of a workstation or of the envelope bearer, the wireless signal transmitter 53 being configured to remotely transmit this identifier with data representative of each signal provided by a sensor 52.

[0081] This allows the wearer of the ring to be identified without risk of error in the allocation of measured doses. It also enables the dosimetric data to be classified by monitoring software.

[0082] Since each device is linked to a single operator, it is possible to precisely monitor each operator's dosimetry in real time while estimating the ambient dose rates of their working environment. The device described in this invention thus allows the wearer and / or a supervisor to know, in real time, the ionizing radiation flux and / or the dose absorbed by the operator wearing the device. If necessary, the operator and each supervisor are alerted in real time if a dose rate or dosimetry threshold is exceeded.

[0083] In some embodiments, the circuit 51 includes a means 68 for detecting the opening of the envelope 50 by an operator and a means 69 for activating the operation of each sensor and the envelope transmitter as soon as the opening of the envelope 50 by an operator is detected. The means 68 for detecting the opening of the envelope 50 can be, for example, a dry contact, a motion sensor, or a temperature sensor.

[0084] In some embodiments, the circuit 51 includes an autonomous memory 70 for storing values ​​captured by the sensor 52 and / or values ​​calculated by the analysis 59. This memory 70 allows, in the event of communication failure, subsequent transmission.

[0085] Thus, envelope 50 allows: to measure the integrated dose and dose rate at the operator's hands, to transmit the measurements in real time to a remote screen and a centralized information system, to configure alert thresholds for dose rate and integrated dose, and to identify the device wearer. to identify oneself at a contactless workstation in order to allow the classification of dosimetric information via monitoring software.

[0086] Although only one 52 sensor is represented in figure 4 The envelope 50 can contain a plurality of sensors sensitive to different types of ionizing radiation.

[0087] Preferably, the interior space of the 50 envelope, particularly between each sensor, the transmitter and the power source, is encased in resin, which increases its resistance to shocks and vibrations.

[0088] Preferably, the envelope 50 also includes a contactless identification method (not shown), such as a barcode or an electronic tag, for example, a passive RFID (Radio Frequency Identification) tag. This identification method allows the envelope to be associated with an activity area, a workstation, or an operator, for traceability and certification purposes.

[0089] We observe, in figure 5 , a device 40 comprising: an envelope 50 carried by a ring 41 on the operator's finger and an envelope 50 in a case 42 clipped onto the operator's glasses or fixed to a headband (not shown).

[0090] The ring 41, which can be worn on the finger by the operator under protective gloves, allows for extremity dosimetry.

[0091] The 42 unit allows dosimetry to be performed at the level of the lens or any specific part of the body.

[0092] In the embodiment shown in figure 5 , the device 40 also includes a portable terminal 43, here worn on the operator's wrist, which includes a receiver for the data emitted by the transmitter 53 of each envelope 50 and a signaling means.

[0093] The signaling device, for example a screen, a light-emitting diode, and / or a loudspeaker, signals to the wearer of the envelopes 50 when the data received by the portable terminal 43 represents instantaneous or integrated radiation exceeding a predetermined limit value. Preferably, the instantaneous radiation limit value and the integrated radiation limit value are adjustable.

[0094] The portable terminal 43 allows the wearer of envelope 50 to obtain an integrated dose measurement as well as the dose rate at the level of envelope 50, in this case at the operator's hands and eyes. The operator is thus alerted in real time to any dose rate or dosimetry threshold exceeded.

[0095] In the embodiment shown in figure 5 The device 40 also includes a local relay 44 for data transmitted by the transmitter 53 of each envelope 50. This local relay 44 retransmits, over a long distance, the data transmitted by the transmitter 53 of each envelope 50. This long-distance data retransmission is carried out using a wired or wireless connection. Preferably, the local relay 44 associates its identifier with the retransmitted data, which makes it possible to determine the zone in which the device 40 is located.

[0096] It is noted that this local relay 44 is all the more necessary when the transmitter 53 is configured to transmit data over a distance less than the communication distance of a wireless local area network.

[0097] In the embodiment shown in figure 5 , the device 40 includes a central receiver 45 of data emitted by the transmitter 53 of each envelope 50 and a system 46 for managing this data.

Claims

1. Individual autonomous device (40) for measuring at least one ionising radiation, characterised in that it comprises: - at least one sensor (22, 52) of each said ionising radiation, supplying an electrical signal representative of the quantity of each said ionising radiation, utilising a bias voltage (21), having a dimension of the order of twenty mm2; - a single signal processing component (29, 60) configured to perform the functions of pre-amplification (23, 56), amplification (24, 57) and formatting (25, 58) of the signal supplied by each sensor (22, 52); - a single component (61) for analysing (59) the signal supplied by the sensor (22, 52) after amplification, this component comprising a wireless signal transmitter (31, 53) configured to remotely transmit data representative of each signal supplied by a sensor; - an autonomous electric power source (27, 54) configured to power each detector and said transmitter, the bias voltage being close to or equal the voltage of the autonomous electric power source, the sensor, the single signal analysis component, the single signal processing component and the power source being embedded in an assembly (50) with a surface area of less than sixty mm2, the total weight of the assembly, sensor, single signal analysis component, single signal processing component and power source being less than ten grammes.

2. Device (40) according to claim 1, which comprises a bias-voltage generator (21, 55), each ionising radiation sensor (22, 52) utilising this bias voltage, wherein the bias voltage is the output voltage from the autonomous electric power source (27, 54) or a voltage stabilised close to the voltage of the autonomous electric power source (27, 54).

3. Device (40) according to claim 2, wherein the single signal processing component (60) has: - a high input impedance; - a low input bias current (< 1 pA); - low noise (< 10 nV / Hz); - a large bandwidth (> 10 MHz).

4. Device (40) according to one of claims 1 to 3, which comprises a single multifunction component (62) to protect (63) the autonomous electric power source against voltage surges, deep discharges and overheating, manage (64) the charge of the autonomous electric power source, and manage (65) the power supply voltage of the single circuit (61) for analysis (59).

5. Device (40) according to claim 4, wherein management (65) of the power supply of the assembly (50) by the single multifunction component (62) is configured as follows: - to supply, at most, two different voltages; - if there is more than one voltage, the voltages are between one-and-a-half and one-half of the voltage of the autonomous electric power source (54).

6. Device (40) according to one of claims 1 to 5, which also comprises a mobile terminal (43) comprising a receiver of the data transmitted by the transmitter (31, 53) of the assembly (50) and a means for signalling to the bearer of the assembly when these data represent a prompt radiation or integrated radiation greater than a predefined limit value.

7. Device (40) according to one of claims 1 to 6, which also comprises a local relay (44) of data transmitted by the transmitter (31, 53) of the assembly (50), a relay configured for the long-distance retransmission of the data transmitted by the transmitter of the assembly.

8. Device (40) according to one of claims 1 to 7, which also comprises a central receiver (45) of data transmitted by the transmitter, and a system (46) for managing these data.

9. Device (40) according to one of claims 1 to 8, which comprises a ring (41) bearing said assembly (50).

10. Device (40) according to one of claims 1 to 9, which comprises a small case (42) comprising said assembly (50), said case able to be clipped onto glasses or incorporated into a strap.

11. Device (40) according to one of claims 1 to 10, which comprises a memory (67) of an identifier of the assembly (50), workstation or bearer of the assembly, the wireless signal transmitter (31, 53) being configured to remotely transmit this identifier with data representative of each signal supplied by a sensor (22, 52).

12. Device (40) according to one of claims 1 to 11, wherein the interior space of the assembly (50), between each sensor (22, 52), the transmitter (31, 53) and the power source (27, 54), is resin-sealed.

13. Device (40) according to one of claims 1 to 11, wherein the transmitter (31, 53) is configured to transmit data at a distance less than the communication distance of a local wireless network.

14. Device (40) according to one of claims 1 to 13, which comprises a means (68) for detecting that the assembly (50) is being borne by an operator, and a means (69) for activating the operation of each sensor (22, 52) and the transmitter (31, 53) of the assembly once it is detected that the assembly is being borne by an operator.

15. Device (40) according to one of claims 1 to 14, wherein the assembly (50) comprises an autonomous memory (70) for storing values captured and / or values calculated.

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